Free-to-paid subscriber tide and revenue mixStacked audience areas are paired with subscription and sponsorship columns
Marketing & Advertising
Newsletter Forecast Calculator
Forecast a hybrid newsletter with free readership, paid membership, and sponsorship. Free and paid subscribers are modeled as connected stocks: upgrades leave the free population and enter paid membership, while each stock retains its own churn behavior. Revenue is split between average paid subscribers and sold delivered sponsor inventory before recurring operating cost.
How to use the newsletter forecast calculator
Forecast free readership and paid membership as two connected subscriber stocks
- Enter the starting free and paid subscriber populations from the same month-end snapshot.
- Set month-one free acquisition, its expected growth, free churn, free-to-paid conversion, and paid churn.
- Enter the paid subscription price to estimate recurring membership revenue.
- Define sends, sponsor slots, sell-through, delivery, and CPM to estimate monetized sponsor inventory.
- Compare monthly revenue with the recurring operating cost and inspect the full twelve-month ledger.
Newsletter business model
Growth, conversion, and monetization act on different bases
Detailed calculation process
Roll both subscriber stocks before pricing monthly revenue
Freem,end = Freem,start − churnfree − upgrades + acquisitionmFree churn and upgrades are calculated from the starting free stock.
Paidm,end = Paidm,start − churnpaid + upgradesUpgrades transfer people between stocks rather than creating duplicate subscribers.
Subscription revenuem = average paid stockm × monthly priceThe average stock approximates subscribers active during the month.
Sponsor revenuem = average audience × sends × delivery × slots × sell-through / 1,000 × CPMOnly delivered and sold inventory is monetized.
Month-one worked example
The default model transfers 960 free subscribers into paid membership
Free churn = 80,000 × 2.4% = 1,920Free-to-paid upgrades = 80,000 × 1.2% = 960Ending free = 80,000 − 1,920 − 960 + 4,500 = 81,620Paid churn = 3,200 × 3.0% = 96Ending paid = 3,200 − 96 + 960 = 4,064Average paid stock = (3,200 + 4,064) / 2 = 3,632Subscription revenue = 3,632 × $12 = $43,584 Sponsor revenue is calculated independently from delivered audience, inventory, sell-through, and CPM. This prevents a paid-conversion assumption from silently increasing the sponsor price.
Forecast controls
Reconcile stock movements before trusting revenue
- Use active, marketable free subscribers rather than the lifetime signup total.
- Keep free churn and paid churn as separate cohort behaviors.
- Measure upgrades before removing paid subscribers from the free segment.
- Base sponsor CPM on sold delivered inventory, not nominal list size.
- Model annual-plan cash timing separately from monthly earned revenue.
Model limitations
The forecast uses one average cohort behavior per stock
It excludes cohort aging, reactivation, upgrades from prior-month campaign timing, annual billing, discounts, refunds, taxes, payment failures, sponsor make-goods, seasonality, inventory conflicts, acquisition cost, capacity limits, and uncertainty.
Decision interpretation
Identify whether growth is audience-led, membership-led, or inventory-led
A growing free stock with weak paid conversion can still support sponsorship, while a smaller high-conversion audience can support membership revenue. Use the separate revenue columns and stock movements to choose the constraint that deserves investment.
Practical examples
Newsletter Forecast Calculator in real planning situations
- Project whether free acquisition outpaces free churn and paid upgrades over twelve months.
- Estimate paid membership revenue without double-counting upgraded readers in the free list.
- Compare subscription revenue with sponsor inventory monetization and identify the first positive month.
Important note
Before relying on this result
This deterministic forecast excludes cohort aging, reactivation, annual billing, discounts, refunds, payment failures, taxes, sponsor make-goods, seasonality, acquisition cost, inventory conflicts, capacity constraints, and uncertainty.
Additional Newsletter Forecast Calculator questions
Why use average paid subscribers for monthly revenue?
It approximates subscribers active during the month instead of assuming every upgrade occurred on the first day.
Are upgrades counted as new total subscribers?
No. They transfer from free to paid, so the combined population changes only through acquisition and churn.
How is sponsorship revenue calculated?
Average total audience is multiplied by sends, delivery, sponsor slots, sell-through, and delivered CPM.
Does the forecast model annual paid plans?
No. It treats price as earned monthly revenue; annual cash timing and deferred revenue require a separate schedule.